Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-345 Class Draft
Insufficient Verification of Data Authenticity
This vulnerability occurs when an application fails to properly check where data comes from or confirm its legitimacy, allowing untrusted or forged information to be processed as valid.
Definition
What is CWE-345?
This vulnerability occurs when an application fails to properly check where data comes from or confirm its legitimacy, allowing untrusted or forged information to be processed as valid.
Insufficient verification of data authenticity is a common root cause for security flaws like spoofing, CSRF, and replay attacks. It happens when developers trust data based solely on its apparent format or origin, without enforcing strong cryptographic signatures, secure tokens, or proper chain-of-trust validation. Attackers exploit this by tampering with requests, forging headers, or replaying captured data to impersonate users, bypass authorization, or trigger unauthorized actions.
To prevent this, always cryptographically verify the source and integrity of critical data—such as session tokens, API requests, and file uploads—using standards like digital signatures, anti-CSRF tokens, and secure challenge-response mechanisms. Managing these validation checks consistently across a complex application landscape is challenging. An ASPM platform like Plexicus can automatically detect missing authenticity checks across your codebase and runtime, using AI to generate precise remediation guidance, ensuring your verification logic is robust and uniformly applied.
Real-world impact
Real-world CVEs caused by CWE-345
-
Distributed Control System (DCS) does not sign firmware images and only relies on insecure checksums for integrity checks
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Distributed Control System (DCS) does not sign firmware images and only relies on insecure checksums for integrity checks
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Remote Terminal Unit (RTU) does not use signatures for firmware images and relies on insecure checksums
How attackers exploit it
Step-by-step attacker path
- 1
Identify a code path that handles untrusted input without validation.
- 2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
- 3
Deliver the payload through a normal request and observe the application's reaction.
- 4
Iterate until the response leaks data, executes attacker code, or escalates privileges.
Vulnerable code example
Vulnerable pseudo
MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
// Untrusted input flows directly into the sensitive sink.
return executeUnsafe(input);
} Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-345
- Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
- Implementation Validate input at trust boundaries; use allowlists, not denylists.
- Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
- Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
- Operation Monitor logs for the runtime signals listed in the next section.
Detection signals
How to detect CWE-345
CWE-345
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Frequently asked questions What is CWE-345?
How serious is CWE-345?
What languages or platforms are affected by CWE-345?
How can I prevent CWE-345?
How does Plexicus detect and fix CWE-345?
Where can I learn more about CWE-345?
Frequently asked questions
What is CWE-345?
This vulnerability occurs when an application fails to properly check where data comes from or confirm its legitimacy, allowing untrusted or forged information to be processed as valid.
How serious is CWE-345?
MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.
What languages or platforms are affected by CWE-345?
MITRE lists the following affected platforms: ICS/OT.
How can I prevent CWE-345?
Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.
How does Plexicus detect and fix CWE-345?
Plexicus's SAST engine matches the data-flow signature for CWE-345 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.
Where can I learn more about CWE-345?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/345.html. You can also reference OWASP and NIST documentation for adjacent guidance.
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